ecu light when coasting

weird problem just started on my 1998 1kz-te supercustom. getting worse too. when coasting down a steep hill the engine check light comes on. eventually goes out after a few sec, but lately is coming on more often and staying on longer. the error code its throwing is 14, which i believe relates to frozen fuel, blocked filter, engine timing control valve or fuel pump fault.

what would be the likely cause from coasting downhill? sometimes does it even when using light throttle. but ALWAYS downhill on a reasonable gradient.

Why coast? The ECU will shut off fuel, the engine will provide engine braking, what are you trying to gain besides an out of control vehicle?

umm, to clarify i dont mean coast out of gear or anything. i just mean going down a hill off throttle, engine braking... terminology not perfect sorry..

Ah right, sorry for going for the throat.

On tickover down hill, getting worse or for longer periods.

Downhill should help fuel flow.

Does it do the same with a full tank? There is a pick up filter in the tank that may be partially blocked.

yea it does do it with a full tank too unfortunately. seems a little bizzare...

Well a new fuel filter is cheap enough to try.......

true might as well give it a try, are they easy to fit?

Filter yes worth a try.

I'd also check all the fuel lines, maybe one is soft and collapsing?

Easy job once you unbolt the holder....worth checking the filter water drain under the filter just before though...possibly its almost full and needing draining?.......It has a sensor to indicate when full, but not sure which dash light it activates..........

So I had the local toyota dealership replace the fuel filter. Problem is still happening. One would hope that they drained any water when replacing the filter, I would assume you cant do one without the other anyway? Its bizzare it only does it downhill... Im tempted to unplug the water sensor and see what happens when going downhill... dodgy sensor?

Another issue I have is a terribly rough start when cold. It almost feels like the engine is giving a massive miss or pre ignite on startup crank when the engine is warm. I have had engine mounts checked and they are fine. It doesn't do it when cold, only a massive shudder when hot. I doubt the two issues are related tho...? The engine runs mint and never misses a beat apart from these two weird issues...

or, if these problems were to be related could it be the timing control valve... the ecu code is 14, one solution refers to timing control valve. I dont know what this valve does, but could it cause rough start..?

Some developments, after trying a new filter, checking the timing control valve my mechanic decided to talk to someone who had experienced this issue before. Apparently they had struck it before and made it their hobby to fix... something about the fuel pump getting fooled into thinking it has poor fuel flow due to a feed pipe in the wrong place... anyhow, the mechanic adjusted the fuel pump timing(apparently?), which made the problem worse... so he then re adjusted, and touch wood not a problem since

Except it still starts very rough sometimes, just a huge "kick" on fire up, mainly when hot...